1. Field of the Invention
The invention relates to a network element interconnection management system.
2. Description of the Prior Art
A network element interconnection management system includes management hardware and software enabling it to set up paths in the network element. Logically, all interconnections must be possible within the network element.
An interconnection operation entails setting up a path in the network element from an input connection point of the network element to any output connection point of the element.
To this end the management system must know the number of input connection points (incoming fibers, for example) and the number of output connection points (outgoing fibers, for example) of the network element.
Unfortunately, in practice, there are limitations which do not allow all of the interconnections which logically would seem to be possible.
The algorithms defining information models relating to the connection points of a network element which already exist for controlling network elements do not give any description of possible interconnection limitations of the network element.
At present the algorithms do not obtain the information from the network itself but from a predetermined description which is necessarily static and which is provided by the vendor of the system.
There can be various reasons for interconnection limitations in a network element:
a network element may be incapable of interconnecting certain connection points (or ports) because of a technological limitation. For example, the wavelength interconnection algorithm is not capable of making an interconnection between an incoming fiber transporting a signal at one wavelength and an outgoing fiber transporting the signal at another wavelength, because of an initial configuration of the hardware which cannot be changed,
a network element may not be fully equipped (for cost reasons). This is an equipment level problem and interconnection may then never be possible, because of limitations associated with the presence of the static equipment,
a network element may never be capable of supporting two particular interconnections at the same time because they would necessitate use of a hardware resource of the network element that cannot be shared (for example, a circuit element needed to set up two distinct paths),
a network element may not support an interconnection imposed by an earlier interconnection. The network element allocates internal resources to support the interconnections and an interconnection that has previously been set up may lead to an interconnection limitation that would not have occurred if resources had been allocated in a different order.
This problem can be solved by reallocating the hardware resources allocated to the interconnections. This procedure, referred to as rearrangement, may or may not temporarily interfere with traffic already set up in the network element.
A limitation can be identified as:
a static interconnection limitation (due to hardware or software), in which case the network element is never able to establish some interconnections,
a dynamic interconnection limitation (due to hardware or software), in which case an interconnection capacity may be impossible at a given time for historical reasons (because of earlier interconnections). In this case there is one or more solutions to the problem of re-establishing interconnection capacity, by carrying out a rearrangement.
In most electrically switched networks, the management system uses data which describes the characteristics of the hardware. The problem of a static interconnection limitation can of course arise if the hardware is inadequate.
The network element static interconnection information is not stored in the network element and the network element management system must obtain this information from another information base (generally a document defining the particular product).
Dynamic interconnection limitations are a problem which is new because it stems from network elements whose number of transmission resources is not fixed, and in this case optical network elements have configuration capacities which are dynamic, i.e. which can be modified from time t to time t+1. At present there is no known solution to this problem.
The object of the present invention is to address the above problems.
The proposed system in accordance with the invention enables the management system and more particularly the path search algorithm used in the system to take decisions based on an exact knowledge of what is happening in the network element.
The present invention consists in a system for managing interconnections between connection points of a network element including the use of an information model, the network element being controlled by a management center, which management system includes:
means for establishing the information model on the basis of initial data and allowing for limitations in the network element at a given time,
means for updating the model, and
means for communicating the model and its updates to the management center to enable it to set up paths in the network element.
The means for establishing the information model include:
means for defining all connection points as objects that can be interconnected, producing an initial object matrix, and
means for modifying the initial object matrix, by adding for each object the set of all unallocated objects to which it can be connected or the set of all objects already allocated to which it temporarily cannot be connected and solutions enabling interconnection with those objects, to obtain a new updated object matrix.
The means for updating the new matrix include means for determining solutions for setting up interconnections using operations of disconnecting established interconnections and/or of rearranging one or more established interconnections and writing those solutions for the object concerned.